Evaluation of CO₂ geological sequestration potential and target optimization of the saline aquifer in the Chang 10_-3 sub-member of YuShen area

Assessing the potential of CO₂ geological storage and selecting advantageous targets are the key to the geological storage of CO₂ in saline aquifers. At present, the evaluation methods of CO₂ geological storage potential are complex, the parameters are difficult to obtain, the site selection methods are diverse, and the site selection indicators are not uniform. In this paper, the stratigraphic division and correlation, lithology and physical property interpretation of the Upper Permian ShiQianFeng formation to the Upper Triassic YanChang formation in YuLin-ShenMu area (Hereinafter referred to as “YuShen” area) have been carried out by using drilling, logging and well completion data, the Saline aquifer of Chang 10_-3 sub-member of YanChang formation of Upper Triassic is the most suitable for CO₂ geological storage in YuShen area. According to the distribution characteristics of underground Saline aquifer, the storage potential of it is evaluated by using the volumetric method, combined with the surface environment conditions of YuShen area, the paper realizes the comprehensive site selection of underground+ground and puts forward 7 important evaluation indexes that affect the site selection. Finally, based on the target optimization block, the evaluation and ranking of target area are carried out by AHP+Fuzzy mathematics comprehensive evaluation method. The results show that the average porosity of the Chang 10_-3 sub-member is 9.40%, the permeability is 1.09mD, the average thickness of the saline aquifer is 37m, and the storage potential is about 5.14×10⁸ t. The delineated block A4 is the most suitable high-quality target area for CO₂ geological storage, which has the conditions to give priority to CCS projects, and can provide guidance for site selection and potential evaluation for surrounding high-carbon emission enterprises to implement CCS projects nearby.